Bistable display devices may include smart glass. Smart glass generally refers to glass materials that change transparency upon an application of a voltage, heat, or light. Active chromogenic materials are a class of materials that may change light transmission properties when voltage is applied. Active chromogenic materials may be used in products such as smart glass, smart film, smart windows, switchable glass, and intelligent glass devices.
Types of smart glass devices may be differentiated based on fabrication technology; liquid crystals, polymer dispersed liquid crystals, electrochromic, suspended particle devices, reflective hydrides and others, as is known in the art.
Smart glass may be used in a range of industry sectors, including construction, transportation, aerospace, electronics, consumer products, optics, energy and sensors.
Smart glass devices may be powered by an appropriate power source. Power requirements may depend on the type of smart glass device. In some applications a knob or switch is used to regulate the voltage applied to the smart glass device. This gives users the ability to control light transmission properties of the smart glass device through a physical interface located on or near the smart glass device.
Monochrome display devices display images, text, and/or patterns in one colour or in shades of one colour. Images using only shades of grey (with or without black and/or white) are grayscale or black-and-white images. A monochromatic image may be black and white, grayscale, or other combinations containing only tones of a single colour.
Monochrome display devices may include bistable displays such as electronic paper or e-paper. Electronic paper can switch between black and white states in order to display the monochromatic image. As bistable displays can maintain the display state without requiring a continuous electrical field, costs of operating such display devices may be reduced. Due to the properties of electronic paper, electronic paper lacks the ability to become transparent.
Conventional display devices such as polymer dispersed liquid crystals (PDLC) may not be bistable. Instead, the liquid crystals are by default in an opaque state. The liquid crystals align in parallel to achieve a transparent state when an electrical field applied to them. In these devices, the transparent state remains only as long as electrical current is being applied. Once the electrical field is turned off, the liquid crystals resort back to a random arrangement resulting in scattering of light and an opaque, “milky white” appearance occurs.